At my favorite local coffee shop, they have a big article posted on their bulletin board about how most European riders drink some espresso before going out each day. It seems logical that caffene would get you going.
If you read the ingredients on such things as Gu and Power Gel, many of them feature something that acts like a stimulant.
And, I read somewhere that now that the UCI is really cracking down on doping, the caffene consumption in the peleton has risen dramatically.